diff options
Diffstat (limited to 'gnulib-m4/malloc.m4')
| -rw-r--r-- | gnulib-m4/malloc.m4 | 198 |
1 files changed, 125 insertions, 73 deletions
diff --git a/gnulib-m4/malloc.m4 b/gnulib-m4/malloc.m4 index ee6df5c3..a95e33db 100644 --- a/gnulib-m4/malloc.m4 +++ b/gnulib-m4/malloc.m4 @@ -1,12 +1,24 @@ # malloc.m4 -# serial 34 -dnl Copyright (C) 2007, 2009-2024 Free Software Foundation, Inc. +# serial 46 +dnl Copyright (C) 2007, 2009-2026 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. - -# This is adapted with modifications from upstream Autoconf here: -# https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/functions.m4?id=v2.70#n949 +dnl This file is offered as-is, without any warranty. + +m4_version_prereq([2.73], [], [ +# Modules that use this macro directly or indirectly should depend +# on extensions-aix, so that _LINUX_SOURCE_COMPAT gets defined +# before this macro gets invoked. This helps on AIX 7.2 and earlier +# if !(__VEC__ || __AIXVEC), and doesn't hurt otherwise. +# +# This is copied from upstream Autoconf here: +# https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/functions.m4?id=1f38316f6af7bf63e5e7dd187ff6456e07ad743e#n971 +# _AC_FUNC_MALLOC_IF(IF-WORKS, IF-NOT[, UNKNOWN-ASSUME]) +# ------------------------------------------------------ +# If 'malloc (0)' returns nonnull, run IF-WORKS, otherwise, IF-NOT. +# If it is not known whether it works, assume the shell word UNKNOWN-ASSUME, +# which should end in "yes" or in something else (the latter is the default). AC_DEFUN([_AC_FUNC_MALLOC_IF], [ AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles @@ -15,61 +27,81 @@ AC_DEFUN([_AC_FUNC_MALLOC_IF], [AC_RUN_IFELSE( [AC_LANG_PROGRAM( [[#include <stdlib.h> - ]], - [[void *p = malloc (0); - void * volatile vp = p; - int result = !vp; + /* Use pmalloc to test; 'volatile' prevents the compiler + from optimizing the malloc call away. */ + void *(*volatile pmalloc) (size_t) = malloc;]], + [[void *p = pmalloc (0); + int result = !p; free (p); - return result;]]) - ], + return result;]])], [ac_cv_func_malloc_0_nonnull=yes], [ac_cv_func_malloc_0_nonnull=no], - [case "$host_os" in - # Guess yes on platforms where we know the result. - *-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \ - | gnu* | *-musl* | midipix* | midnightbsd* \ - | hpux* | solaris* | cygwin* | mingw* | windows* | msys* ) - ac_cv_func_malloc_0_nonnull="guessing yes" ;; - # If we don't know, obey --enable-cross-guesses. - *) ac_cv_func_malloc_0_nonnull="$gl_cross_guess_normal" ;; - esac - ]) - ]) + [AS_CASE([$host_os], + [# Guess yes on platforms where we know the result. + *-gnu* | freebsd* | netbsd* | openbsd* | bitrig* \ + | gnu* | *-musl* | midipix* | midnightbsd* \ + | hpux* | solaris* | cygwin* | mingw* | windows* | msys*], + [ac_cv_func_malloc_0_nonnull="guessing yes"], + [# Guess as follows if we don't know. + ac_cv_func_malloc_0_nonnull=m4_default([$3], ["guessing no"])])])]) AS_CASE([$ac_cv_func_malloc_0_nonnull], [*yes], [$1], [$2]) ])# _AC_FUNC_MALLOC_IF +]) + +# gl_FUNC_MALLOC_0_NONNULL +# ------------------------ +# If 'malloc (0)' returns nonnull define HAVE_MALLOC_0_NONNULL. +# Also, set ac_cv_func_malloc_0_nonnull to a string that ends in +# "yes", otherwise set it to something else. If unknown whether +# malloc (0) works, guess as normal for cross-builds. +AC_DEFUN([gl_FUNC_MALLOC_0_NONNULL], +[ + _AC_FUNC_MALLOC_IF( + [AC_DEFINE([HAVE_MALLOC_0_NONNULL], [1], + [Define to 1 if malloc (0) returns nonnull.])], + [], + ["$gl_cross_guess_normal"]) +]) # gl_FUNC_MALLOC_GNU # ------------------ -# Replace malloc if it is not compatible with GNU libc. +# Test whether malloc (0) is compatible with GNU libc. +# Replace malloc if not. +# Define HAVE_MALLOC_0_NONNULL if malloc (0) returns nonnull (except upon +# out-of-memory). +# Define HAVE_MALLOC_PTRDIFF if malloc (N) reliably fails when N exceeds +# PTRDIFF_MAX. AC_DEFUN([gl_FUNC_MALLOC_GNU], [ AC_REQUIRE([gl_STDLIB_H_DEFAULTS]) AC_REQUIRE([gl_FUNC_MALLOC_POSIX]) + AC_REQUIRE([gl_FUNC_MALLOC_0_NONNULL]) - dnl Through the dependency on module extensions-aix, _LINUX_SOURCE_COMPAT - dnl gets defined already before this macro gets invoked. This helps - dnl if !(__VEC__ || __AIXVEC), and doesn't hurt otherwise. - - REPLACE_MALLOC_FOR_MALLOC_GNU="$REPLACE_MALLOC_FOR_MALLOC_POSIX" - if test $REPLACE_MALLOC_FOR_MALLOC_GNU = 0; then - _AC_FUNC_MALLOC_IF([], [REPLACE_MALLOC_FOR_MALLOC_GNU=1]) - fi + AS_CASE([$ac_cv_func_malloc_0_nonnull], + [*yes], + [REPLACE_MALLOC_FOR_MALLOC_GNU=$REPLACE_MALLOC_FOR_MALLOC_POSIX], + [REPLACE_MALLOC_FOR_MALLOC_GNU=1]) ]) # gl_FUNC_MALLOC_PTRDIFF # ---------------------- -# Test whether malloc (N) reliably fails when N exceeds PTRDIFF_MAX, -# and replace malloc otherwise. +# Test whether malloc (N) reliably fails when N exceeds PTRDIFF_MAX. +# Define HAVE_MALLOC_PTRDIFF if yes. +# Replace malloc if not. AC_DEFUN([gl_FUNC_MALLOC_PTRDIFF], [ AC_REQUIRE([gl_STDLIB_H_DEFAULTS]) AC_REQUIRE([gl_CHECK_MALLOC_PTRDIFF]) - test "$gl_cv_malloc_ptrdiff" = yes || REPLACE_MALLOC_FOR_MALLOC_POSIX=1 + AS_IF([test "$gl_cv_malloc_ptrdiff" = yes], + [AC_DEFINE([HAVE_MALLOC_PTRDIFF], 1, + [Define to 1 if malloc-like functions do not allocate objects + larger than PTRDIFF_MAX bytes.])], + [REPLACE_MALLOC_FOR_MALLOC_POSIX=1]) ]) -# Test whether malloc, realloc, calloc refuse to create objects +# Test whether malloc, calloc refuse to create objects # larger than what can be expressed in ptrdiff_t. -# Set gl_cv_func_malloc_gnu to yes or no accordingly. +# Set gl_cv_func_malloc_gnu. AC_DEFUN([gl_CHECK_MALLOC_PTRDIFF], [ AC_CACHE_CHECK([whether malloc is ptrdiff_t safe], @@ -113,64 +145,84 @@ AC_DEFUN([gl_FUNC_MALLOC_POSIX], AC_REQUIRE([gl_STDLIB_H_DEFAULTS]) AC_REQUIRE([gl_FUNC_MALLOC_PTRDIFF]) AC_REQUIRE([gl_CHECK_MALLOC_POSIX]) - if test "$gl_cv_func_malloc_posix" = yes; then - AC_DEFINE([HAVE_MALLOC_POSIX], [1], - [Define if malloc, realloc, and calloc set errno on allocation failure.]) - else - REPLACE_MALLOC_FOR_MALLOC_POSIX=1 - fi + case "$gl_cv_func_malloc_posix" in + *yes) + AC_DEFINE([HAVE_MALLOC_POSIX], [1], + [Define if malloc and calloc set errno on allocation failure.]) + ;; + *) + REPLACE_MALLOC_FOR_MALLOC_POSIX=1 + ;; + esac ]) -# Test whether malloc, realloc, calloc set errno to ENOMEM on failure. -# Set gl_cv_func_malloc_posix to yes or no accordingly. +# Test whether malloc, calloc set errno to ENOMEM on failure. +# Set gl_cv_func_malloc_posix to *yes or *no accordingly. AC_DEFUN([gl_CHECK_MALLOC_POSIX], [ AC_REQUIRE([AC_CANONICAL_HOST]) - AC_CACHE_CHECK([whether malloc, realloc, calloc set errno on failure], + AC_CACHE_CHECK([whether malloc, calloc set errno on failure], [gl_cv_func_malloc_posix], [ dnl It is too dangerous to try to allocate a large amount of memory: dnl some systems go to their knees when you do that. So assume that dnl all Unix implementations of the function set errno on failure, dnl except on those platforms where we have seen 'test-malloc-gnu', - dnl 'test-realloc-gnu', 'test-calloc-gnu' fail. + dnl 'test-realloc-posix', 'test-calloc-gnu' fail. For platforms + dnl where only 'test-realloc-posix', see realloc.m4. case "$host_os" in mingw* | windows*) - gl_cv_func_malloc_posix=no ;; - irix* | solaris*) - dnl On IRIX 6.5, the three functions return NULL with errno unset - dnl when the argument is larger than PTRDIFF_MAX. - dnl On Solaris 11.3, the three functions return NULL with errno set + dnl Old MSVCRT from 2001 did not set errno=ENOMEM when malloc failed. + dnl More recent MSVCRT from 2019 does so. + dnl UCRT is the successor of MSVCRT. Assume that UCRT does so as well. + AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM( + [[#include <stdio.h> + #ifndef _UCRT + msvcrt yuck + #endif + ]], + [[]]) + ], + [gl_cv_func_malloc_posix="guessing yes"], + [gl_cv_func_malloc_posix="guessing no"]) + ;; + solaris*) + dnl On Solaris 11.3, the three functions might fail with errno set dnl to EAGAIN, not ENOMEM, when the argument is larger than - dnl PTRDIFF_MAX. + dnl PTRDIFF_MAX. See: + dnl https://lists.gnu.org/r/bug-gnulib/2021-05/msg00052.html dnl Here is a test program: + m4_divert_push([KILL]) #include <errno.h> +#include <stddef.h> #include <stdio.h> +#include <stdint.h> #include <stdlib.h> -#define ptrdiff_t long -#ifndef PTRDIFF_MAX -# define PTRDIFF_MAX ((ptrdiff_t) ((1UL << (8 * sizeof (ptrdiff_t) - 1)) - 1)) -#endif -int main () +#define TEST_CALL(call) \ + do { \ + void *p = call; \ + if (p) \ + fprintf (stderr, "returned %p (incorrect success)\n", p); \ + else if (errno == ENOMEM) \ + perror ("correct failure"); \ + else \ + perror ("incorrect failure (wrong errno)"); \ + free (p); \ + } while (0) + +int +main () { - void *p; - - fprintf (stderr, "PTRDIFF_MAX = %lu\n", (unsigned long) PTRDIFF_MAX); - - errno = 0; - p = malloc ((unsigned long) PTRDIFF_MAX + 1); - fprintf (stderr, "p=%p errno=%d\n", p, errno); - - errno = 0; - p = calloc (PTRDIFF_MAX / 2 + 1, 2); - fprintf (stderr, "p=%p errno=%d\n", p, errno); - - errno = 0; - p = realloc (NULL, (unsigned long) PTRDIFF_MAX + 1); - fprintf (stderr, "p=%p errno=%d\n", p, errno); - + size_t big = PTRDIFF_MAX; + TEST_CALL (malloc (big + 1)); + TEST_CALL (calloc (big / 2 + 1, 2)); + TEST_CALL (realloc (NULL, big + 1)); + void *small = malloc (1); + TEST_CALL (realloc (small, big + 1)); + free (small); return 0; } m4_divert_pop([KILL]) |